1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * IA-64 Huge TLB Page Support for Kernel.
  4 *
  5 * Copyright (C) 2002-2004 Rohit Seth <rohit.seth@intel.com>
  6 * Copyright (C) 2003-2004 Ken Chen <kenneth.w.chen@intel.com>
  7 *
  8 * Sep, 2003: add numa support
  9 * Feb, 2004: dynamic hugetlb page size via boot parameter
 10 */
 11
 12#include <linux/init.h>
 13#include <linux/fs.h>
 14#include <linux/mm.h>
 15#include <linux/hugetlb.h>
 16#include <linux/pagemap.h>
 17#include <linux/module.h>
 18#include <linux/sysctl.h>
 19#include <linux/log2.h>
 20#include <asm/mman.h>
 21#include <asm/tlb.h>
 22#include <asm/tlbflush.h>
 23
 24unsigned int hpage_shift = HPAGE_SHIFT_DEFAULT;
 25EXPORT_SYMBOL(hpage_shift);
 26
 27pte_t *
 28huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
 29	       unsigned long addr, unsigned long sz)
 30{
 31	unsigned long taddr = htlbpage_to_page(addr);
 32	pgd_t *pgd;
 33	p4d_t *p4d;
 34	pud_t *pud;
 35	pmd_t *pmd;
 36	pte_t *pte = NULL;
 37
 38	pgd = pgd_offset(mm, taddr);
 39	p4d = p4d_offset(pgd, taddr);
 40	pud = pud_alloc(mm, p4d, taddr);
 41	if (pud) {
 42		pmd = pmd_alloc(mm, pud, taddr);
 43		if (pmd)
 44			pte = pte_alloc_map(mm, pmd, taddr);
 45	}
 46	return pte;
 47}
 48
 49pte_t *
 50huge_pte_offset (struct mm_struct *mm, unsigned long addr, unsigned long sz)
 51{
 52	unsigned long taddr = htlbpage_to_page(addr);
 53	pgd_t *pgd;
 54	p4d_t *p4d;
 55	pud_t *pud;
 56	pmd_t *pmd;
 57	pte_t *pte = NULL;
 58
 59	pgd = pgd_offset(mm, taddr);
 60	if (pgd_present(*pgd)) {
 61		p4d = p4d_offset(pgd, addr);
 62		if (p4d_present(*p4d)) {
 63			pud = pud_offset(p4d, taddr);
 64			if (pud_present(*pud)) {
 65				pmd = pmd_offset(pud, taddr);
 66				if (pmd_present(*pmd))
 67					pte = pte_offset_map(pmd, taddr);
 68			}
 69		}
 70	}
 71
 72	return pte;
 73}
 74
 75#define mk_pte_huge(entry) { pte_val(entry) |= _PAGE_P; }
 76
 77/*
 78 * Don't actually need to do any preparation, but need to make sure
 79 * the address is in the right region.
 80 */
 81int prepare_hugepage_range(struct file *file,
 82			unsigned long addr, unsigned long len)
 83{
 84	if (len & ~HPAGE_MASK)
 85		return -EINVAL;
 86	if (addr & ~HPAGE_MASK)
 87		return -EINVAL;
 88	if (REGION_NUMBER(addr) != RGN_HPAGE)
 89		return -EINVAL;
 90
 91	return 0;
 92}
 93
 94int pmd_huge(pmd_t pmd)
 95{
 96	return 0;
 97}
 98
 99int pud_huge(pud_t pud)
100{
101	return 0;
102}
103
104void hugetlb_free_pgd_range(struct mmu_gather *tlb,
105			unsigned long addr, unsigned long end,
106			unsigned long floor, unsigned long ceiling)
107{
108	/*
109	 * This is called to free hugetlb page tables.
110	 *
111	 * The offset of these addresses from the base of the hugetlb
112	 * region must be scaled down by HPAGE_SIZE/PAGE_SIZE so that
113	 * the standard free_pgd_range will free the right page tables.
114	 *
115	 * If floor and ceiling are also in the hugetlb region, they
116	 * must likewise be scaled down; but if outside, left unchanged.
117	 */
118
119	addr = htlbpage_to_page(addr);
120	end  = htlbpage_to_page(end);
121	if (REGION_NUMBER(floor) == RGN_HPAGE)
122		floor = htlbpage_to_page(floor);
123	if (REGION_NUMBER(ceiling) == RGN_HPAGE)
124		ceiling = htlbpage_to_page(ceiling);
125
126	free_pgd_range(tlb, addr, end, floor, ceiling);
127}
128
129unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
130		unsigned long pgoff, unsigned long flags)
131{
132	struct vm_unmapped_area_info info;
133
134	if (len > RGN_MAP_LIMIT)
135		return -ENOMEM;
136	if (len & ~HPAGE_MASK)
137		return -EINVAL;
138
139	/* Handle MAP_FIXED */
140	if (flags & MAP_FIXED) {
141		if (prepare_hugepage_range(file, addr, len))
142			return -EINVAL;
143		return addr;
144	}
145
146	/* This code assumes that RGN_HPAGE != 0. */
147	if ((REGION_NUMBER(addr) != RGN_HPAGE) || (addr & (HPAGE_SIZE - 1)))
148		addr = HPAGE_REGION_BASE;
149
150	info.flags = 0;
151	info.length = len;
152	info.low_limit = addr;
153	info.high_limit = HPAGE_REGION_BASE + RGN_MAP_LIMIT;
154	info.align_mask = PAGE_MASK & (HPAGE_SIZE - 1);
155	info.align_offset = 0;
156	return vm_unmapped_area(&info);
157}
158
159static int __init hugetlb_setup_sz(char *str)
160{
161	u64 tr_pages;
162	unsigned long long size;
163
164	if (ia64_pal_vm_page_size(&tr_pages, NULL) != 0)
165		/*
166		 * shouldn't happen, but just in case.
167		 */
168		tr_pages = 0x15557000UL;
169
170	size = memparse(str, &str);
171	if (*str || !is_power_of_2(size) || !(tr_pages & size) ||
172		size <= PAGE_SIZE ||
173		size >= (1UL << PAGE_SHIFT << MAX_ORDER)) {
174		printk(KERN_WARNING "Invalid huge page size specified\n");
175		return 1;
176	}
177
178	hpage_shift = __ffs(size);
179	/*
180	 * boot cpu already executed ia64_mmu_init, and has HPAGE_SHIFT_DEFAULT
181	 * override here with new page shift.
182	 */
183	ia64_set_rr(HPAGE_REGION_BASE, hpage_shift << 2);
184	return 0;
185}
186early_param("hugepagesz", hugetlb_setup_sz);